1.4 Diagnostics

1.4 Diagnostics

During execution, FunnelWeb proceeds cautiously with each of

its phases, only proceeding with the next phase if the previous

Tutorial

phase has been successful. This means that, when debugging a

FunnelWeb file, you may find that the number of errors

Developer

increases

  after you fix some of them, as you will be exposing

yourself to the next FunnelWeb phase.

Reference

FunnelWeb employs five levels of diagnostics at different

1 Introduction

levels of severity. Severity is defined in terms of the level of

2 Interface

activity at which the diagnostic causes FunnelWeb to abort.

3 Scanner

Warning:

 A warning does not cause FunnelWeb

4 Parser

to terminate or curtail its operation in any way, but

5 Analyser

serves merely to warn the user of particular

6 Tangle

conditions that might be symptomatic of deeper

7 Weave

problems.

8 Shell

Error:

 An error causes FunnelWeb to terminate

9 Commands

processing of the current input file at the end of the

current phase. For example, if an error occurs

10 Glossary

during scanning, FunnelWeb will continue

11 References

scanning (and possibly generate further scanning

diagnostics), but will not invoke the parser.

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Severe Error:

 A severe error (or "severe" for

short) is the same as an error except that

FunnelWeb terminates the current phase

immediately.

Fatal Error:

 A fatal error causes FunnelWeb not

only to terminate the current phase and run

immediately, but also to terminate total

FunnelWeb processing immediately. A severe

error will not cause a FunnelWeb script to

terminate, but a fatal error will. A fatal error

causes FunnelWeb to return control to the

operating system.

Assertion Error:

 An assertion error occurs if

FunnelWeb detects an internal inconsistency, in

which case FunnelWeb terminates immediately

and ungracefully. Such an error can occur only if

there are bugs in FunnelWeb. With luck, such

errors will be extremely rare.

http://www.ross.net/funnelweb/reference/intro_diagnostics.html (1 of 2) [3/3/2000 10:49:33 PM]